Association between 4-benzamide and an acetylcholinesterase inhibitor, and pharmaceutical compositions containing it

ABSTRACT

Association between 4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamide of formula (I): 
     
       
         
         
             
             
         
       
     
     or an addition salt thereof with a pharmaceutically acceptable acid or base, and an acetylcholinesterase inhibitor. 
     Medicinal products containing the same which are useful in the treatment of cognitive disturbances associated with cerebral ageing and with neurodegenerative diseases.

The present invention relates to a new association between4-{3-[cis-hexahydro-cyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamide offormula (I):

or an addition salt thereof with a pharmaceutically acceptable acid orbase, and an acetylcholinesterase inhibitor, for obtainingpharmaceutical compositions for use in the treatment of cognitivedisturbances associated with cerebral ageing and with neurodegenerativediseases.

4-{3-[cis-Hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamide hasthe characteristic of interacting with central histaminergic systems invivo. These properties provide it with activity in the central nervoussystem and, more especially, in the treatment of cognitive deficienciesassociated with cerebral ageing and with neurodegenerative diseases.

4-{3-[cis-Hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamide, itspreparation and its therapeutic use have been described in PatentApplication WO2005/089747.

The Applicant has now found that4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}-benzamide offormula (I), or an addition salt thereof with a pharmaceuticallyacceptable acid or base, used in association with anacetylcholinesterase inhibitor has valuable properties for the treatmentof cognitive disturbances associated with cerebral ageing and withneurodegenerative diseases.

Neurodegenerative diseases related to cerebral ageing such asAlzheimer's disease are characterised by disturbances of memory andcognitive dysfunction. The cognitive disturbances are usually associatedwith a reduction in the ability of neurons to synthesise and releasecertain neurotransmitters. There is moreover observed a progressive lossof synaptic plasticity and of neuronal processes, this neuronal lossbeing accelerated in certain specific regions of the brain. Among thevarious neurotransmitters, central histamine and acetylcholine play acrucial part in the control of cognitive functions (Witkin and Nelson,Pharmacol. & Therap., 2004, 103, 1-20) and their levels have been shownto greatly diminish in patients suffering from Alzheimer's diseasecompared to those observed in healthy elderly people (Panula et al.,Neuroscience, 1998, 82(4), 993-997).

Type H₃ histaminergic receptors, which are especially abundant in thecentral nervous system, are mainly presynaptic modulators of neuraltransmission and are present in a variety of neuronal circuits relevantto cognition (Blandina et al., Learn Mem., 2004, 11(1), 1-8). They actby negatively regulating the release of neurotransmitters such ashistamine, acetylcholine, serotonin, noradrenaline and dopamine. Giventhat histaminergic neurons seem to be largely spared in Alzheimer'sdisease, compounds that are antagonists or inverse agonists of H₃receptors could open the way to new treatments for the cognitivedisturbances related to cerebral ageing.

Conversely, progressive degeneration of cholinergic neurons is observedin the course of Alzheimer's disease. Acetylcholinesterase inhibitorssuch as donepezil are commonly used in the symptomatic treatment ofAlzheimer's disease in order to limit the lowering of acetylcholinelevels in the brain by blocking the action of acetylcholinesterase. Ithas been shown that acetylcholinesterase inhibitors, likeantagonists/inverse agonists of H₃ receptors, make it possible toimprove cognitive properties in various animal models of episodic memoryand working memory (Esbenshade et al., Br. J. Pharmacol., 2008, 154(6),1166-1181; Yuede et al., Behav. Pharmacol., 2007, 18(5-6), 347-363).Improving cognitive functions may therefore be based on two types ofstrategy targeting either histamine or acetylcholine.

The present invention has shown, surprisingly, that the effects ofacetylcholinesterase inhibitors are potentiated by those of4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}-benzamide oraddition salts thereof with a pharmaceutically acceptable acid or base.Accordingly, co-administration of these compounds could make it possibleto improve the cognitive performance of patients compared to the simpleadministration of an acetylcholinesterase inhibitor without, however,increasing the adverse effects associated with the treatment (especiallygastrointestinal disturbances such as nausea or diarrhoea, headaches orfatigue). In other words, treatments involving therapeutic doses ofacetylcholinesterase inhibitor that are lower than those customarilyused in mono-therapy can therefore now be envisaged, with equivalent oreven superior cognitive performance and fewer adverse effects.

This unforeseeable effect makes it possible to envisage usingassociations between4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamide, or anaddition salt thereof, and an acetylcholinesterase inhibitor in thetreatment of cognitive disturbances associated with cerebral ageing andwith neurodegenerative diseases. The cognitive disturbances associatedwith Alzheimer's disease and with Parkinson's disease are beingespecially targeted.

4-{3-[cis-Hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamide isused preferably in the form of an oxalate or hydrochloride within thecontext of the invention.

Among the acetylcholinesterase inhibitors according to the invention,donepezil, rivastigmine and galantamine are especially preferred.Preferably, donepezil is used in the form of a hydrochloride,rivastigmine in the form of a hydrogen tartrate, and galantamine in theform of a hydrobromide.

More especially, the association of4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}-benzamide anddonepezil is used in the treatment of cognitive disturbances associatedwith Alzheimer's disease, whereas the association of4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamide andrivastigmine is preferred in the treatment of cognitive disturbancesassociated with Parkinson's disease.

The invention accordingly relates to use of the association between4-{3-[cis-hexahydro-cyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamide, oraddition salts thereof with a pharmaceutically acceptable acid or base,and an acetylcholinesterase inhibitor in obtaining pharmaceuticalcompositions intended for the treatment of cognitive disturbancesassociated with cerebral ageing and with neurodegenerative diseases.

The invention relates also to pharmaceutical compositions comprising theassociation between4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamide, oraddition salts thereof with a pharmaceutically acceptable acid or base,and an acetylcholinesterase inhibitor in combination with one or morepharmaceutically acceptable excipients.

In the pharmaceutical compositions according to the invention, theproportion of active ingredients by weight (weight of active ingredientsover the total weight of the composition) is preferably from 5 to 50%.

Among the pharmaceutical compositions according to the invention therewill be more especially used those which are suitable for administrationby the oral, parenteral and especially intravenous, per- ortrans-cutaneous, nasal, rectal, perlingual, ocular or respiratory route,more specifically tablets, dragées, sublingual tablets, hard gelatincapsules, glossettes, capsules, lozenges, injectable preparations,aerosols, eye or nose drops, suppositories, creams, ointments, dermalgels etc.

Besides4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamide andthe acetyl-cholinesterase inhibitor compound, the pharmaceuticalcompositions according to the invention comprise one or more excipientsor carriers selected from diluents, lubricants, binders, disintegrationagents, stabilisers, preservatives, absorbents, colourants, sweeteners,flavourings etc.

By way of non-limiting example there may be mentioned:

-   -   as diluents: lactose, dextrose, sucrose, mannitol, sorbitol,        cellulose, glycerol,    -   as lubricants: silica, talc, stearic acid and its magnesium and        calcium salts, polyethylene glycol,    -   as binders: magnesium aluminium silicate, starch, gelatin,        tragacanth, methylcellulose, sodium carboxymethylcellulose and        polyvinylpyrrolidone,    -   as disintegrants: agar, alginic acid and its sodium salt,        effervescent mixtures.

The compounds of the association may be administered simultaneously orsequentially. The administration route is preferably the oral route, andthe corresponding pharmaceutical compositions may allow theinstantaneous or delayed release of the active ingredients. Thecompounds of the association may moreover be administered in the form oftwo separate pharmaceutical compositions, each containing one of theactive ingredients, or in the form of a single pharmaceuticalcomposition, in which the active ingredients are in admixture.

Preference is given to the pharmaceutical compositions being tablets.

The useful dosage regimen varies according to the sex, age and weight ofthe patient, the administration route, the nature of the disorder and ofany associated treatments and ranges from 0.5 mg to 100 mg of4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamide per 24hours, more preferably 5 mg per day. The dose of theacetylcholinesterase inhibitor will be the same as or less than thatused when it is administered on its own. In the case of donepezil, thedosage regimen is from 0.5 mg to 30 mg per day, preferred daily dosesbeing 5 and 10 mg for the donepezil hydrochloride. For rivastigmine, thedosage regimen is from 1 mg to 20 mg per day. Preferred daily doses are3 and 6 mg twice per day when rivastigmine is administered in the formof a tablet, whereas they are 4.6 mg and 9.5 mg per day when the productis presented in the form of a patch. In the case of galantamine, thedosage regimen is from 1 to 30 mg per day, preferred daily doses being16 and 24 mg.

In preferred embodiments of the invention, the association between4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamide(compound S) and donepezil is administered at the following daily doses:

Composition Composition Composition 1 2 3 Hydrochloride of compound S  2mg  5 mg 20 mg (expressed as base) Donepezil hydrochloride 10 mg 10 mg10 mg

Pharmaceutical Composition

-   -   Formula for the preparation of 1000 tablets each containing 5 mg        (expressed as base) of        4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamide        hydrochloride and 10 mg of donepezil hydrochloride:

4-{3-[cis-Hexahydrocyclopenta[c]pyrrol-2(1H)- 5 g yl]propoxy}benzamidehydrochloride (expressed as base) Donepezil hydrochloride 10 g  Maizestarch 20 g  Maltodextrin 7.5 g   Colloidal silica 0.2 g   Sodium starchglycolate 3 g Magnesium stearate 1 g Lactose 55 g 

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the experimental procedure for the contextual serialdiscrimination test.

FIGS. 2-5 show the results obtained using the contextual serialdiscrimination test.

EXAMPLE A Experiment in a Model of Episodic Memory, the ContextualSerial Discrimination Test

The effects of4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamide anddonepezil (both in the form of a hydrochloride), administered on theirown or in combination, were studied using a contextual serialdiscrimination test in the middle-aged (14-15 months old) C57B16 mouse(n=12 per group) (Célérier et al., Learn Mem., 2004, 11(2), 196-204;Tronche et al., Behav. Brain Res., 2010, 215(2): 255-60). In this model,the middle-aged mice have a specific dysfunction of contextual memorycompared to young mice, without a deficiency in spatial memory. Thismodel is relevant for evaluating the effects of products in Alzheimer'sdisease because patients suffering from that form of dementia also havedisturbances of contextual episodic memory, this being the case from avery early stage (Gold and Budson, Expert Rev Neurother., 2008, 8(12):1879-1891).

The mice, placed in a box with raised edges, learn two types ofconsecutive spatial discrimination (D1: white floor, then D2: blackfloor) on a floor with four holes, in which just one of the holes isbaited, the arrangement being opposite in D1 and in D2 (see FIG. 1).Each discrimination is performed on a specific floor (black or white),which constitutes the internal context specific to each discrimination.24 hours after the learning step, the mice are returned to the whitecontextual floor, and the following are measured:

-   -   the percentage of correct responses (i.e. % of lowering the head        into the hole that was baited during the learning exercise on        the white floor),    -   the percentage of interfering responses (i.e. % of lowering the        head into the hole that was baited during the learning exercise        on the black floor, the last context presented to the mice),    -   and the percentage of errors (i.e. % of lowering the head into        the two holes that were not baited during learning, whether on        the white floor or on the black floor (see FIG. 1).

The results show that the middle-aged mice treated with the carrier havea percentage of correct responses which is close to the level of chancein this test on 4-hole boards (≈25%). Following chronic treatment for 9days with donepezil hydrochloride (0.1 mg/kg of base per os), nosignificant improvement in the percentage of correct responses isobserved compared to the carrier (see FIG. 2). In contrast, the level ofcorrect responses increases by more than 60% compared to the carrierfollowing chronic treatment for 9 days with4-{3-[cis-hexahydro-cyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamidehydrochloride at doses of 0.3 and 1 mg/kg of base per os (compoundreferred to as “S” in FIG. 2). Finally, administration of theassociation of4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamide (0.3and 1 mg/kg of base per os) with donepezil (0.1 mg/kg of base per os)results in an increase in the level of correct responses of more than100% compared to the carrier on its own. These results show clearpotentiation of the effects of donepezil in the presence of4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamide.

A very good correlation was moreover observed between the increase inthe level of correct responses and the reduction in the level ofinterfering responses, thereby confirming the specific effect of eachcompound and of their association on contextual memory. Accordingly, theadministration of the association of4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}-benzamide (0.3and 1 mg/kg of base per os) with donepezil (0.1 mg/kg of base per os)significantly increases the power of contextual memory (correctresponses—interfering responses) compared to that observed with thecompounds on their own. This increase that is observed for theassociation cannot be explained by simply adding together the effects ofthe compounds administered on their own and shows synergistic activityof the two compounds when they are co-administered (see FIG. 3).

The results clearly demonstrate that the administration of these twocompounds in association makes it possible to obtain a large synergisticeffect which was entirely unexpected. Pharmacokinetic analyses havemoreover shown that there was no pharmacokinetic-type interactionbetween the two treatments which might justify or interfere with thesynergistic effect described above.

EXAMPLE B Experiment with Rivastimine in the Same Contextual SerialDiscrimination Test

The effects of4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamide andrivastigmine (used in the form of a hydrogen tartrate), administered ontheir own or in combination, were studied using the contextual serialdiscrimination test in the middle-aged C57B16 mouse described in theExample above.

In this model it has been shown that, compared to young mice, themiddle-aged mice have a contextual memory deficit due to the fact thatthe last context in which they learnt the location of the baited hole(i.e. the black floor) substantially interferes with memory of thebaited hole in the first context presented during learning (i.e. thewhite floor). Because of this fact, the elderly mice have negativevalues for the power of contextual memory (correct responses—interferingresponses) because the percentage of interfering responses is higherthan the percentage of correct responses. In contrast, the young micehave a positive power of contextual memory (Tronche et al., Behav. BrainRes., 2010, 215(2): 255-60).

As in the Example above, the results of this study confirm thecontextual memory deficit in middle-aged mice, the mice treated with thecarrier showing a negative contextual memory power of −28% (see FIG. 4).Following chronic treatment for 9 days with rivastigmine at a dose of0.1 mg/kg of base per os, a slight increase in the power of contextualmemory compared to the carrier is observed (−9% versus −28%), but itstill remains negative, the percentage of interfering responses stillbeing greater than the percentage of correct responses, giving rise tothe conclusion that the 0.1 mg/kg dose of rivastigmine is a sub-activedose.

Similarly, the power of contextual memory increases only slightlycompared to the carrier following chronic treatment for 9 days with4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamidehydrochloride at doses of 0.3 and 1 mg/kg of base per os (+6% and +10%,respectively, versus −28%). In contrast, administration of theassociation of rivastigmine (sub-active dose of 0.1 mg/kg of base peros) with4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamide (0.3or 1 mg/kg of base per os) results in a substantial increase in thepower of contextual memory, which then becomes significantly superior (%of correct responses>% of interfering responses), on the one handrelative to the value obtained with the carrier and on the other handrelative to that obtained for rivastigmine on its own (+28% and +28%versus −9%, respectively). These results show clear potentiation of theeffects of rivastigmine at a sub-active dose in the presence of activedoses of4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamide, whichis reflected by an increase in the memory performance of the micetreated with the association.

In this second example too, the increase in the power of contextualmemory observed for the two associations cannot be explained by simplyadding together the effects of the compounds administered on their ownand shows entirely unexpected synergistic activity for the two compoundswhen they are co-administered.

Pharmacokinetic analyses have moreover shown that there was nopharmacokinetic-type interaction between the two treatments which mightjustify or interfere with the synergistic effect described above.

In conclusion, the results presented above demonstrate synergisticactivity between4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamide andrivastigmine in terms of cognitive performance, this being the casewithout any pharmacokinetic interaction.

EXAMPLE C Experiment with Galantamine in the Same Contextual SerialDiscrimination Test

The effects of4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamide andgalantamine (used in the form of a hydrobromide), administered on theirown or in combination, were also studied using the contextual serialdiscrimination test in the middle-aged C57B16 mouse.

As in the Examples above, the results of this study confirm thecontextual memory deficit of middle-aged mice, the mice treated with thecarrier showing a negative contextual memory power of −28% (see FIG. 5).

Following chronic treatment for 9 days with galantamine at a dose of 0.3mg/kg of base per os, there is observed no significant improvement inthe power of contextual memory compared to the carrier (−18% versus−28%), the power remaining markedly negative (% interfering responses>%correct responses); the 0.3 mg/kg dose of galantamine is thereforesub-active. Neither, after chronic treatment for 9 days with4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamidehydrochloride at a dose of 0.3 mg/kg of base per os, does contextualmemory power increase significantly compared to the carrier (−3% versus−28%, respectively).

Moreover, after chronic treatment for 9 days with4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamidehydrochloride at a dose of 1 mg/kg of base per os, it increases onlyslightly compared to the carrier (+9% versus −28%). In contrast,administration of the association of4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamide (0.3and 1 mg/kg of base per os) with galantamine (sub-active dose of 0.3mg/kg of base per os) results in a substantial increase in contextualmemory power, which becomes significantly superior compared to the valueobtained with the carrier on its own (+31% and +24% versus −28%,respectively). These results show clear potentiation of the effects ofgalantamine at a sub-active dose in the presence of a sub-active orslightly active dose of4-{3-[cis-hexahydrocyclo-penta[c]pyrrol-2(1H)-yl]propoxy}benzamide,which is reflected by an increase in the memory performance of the micetreated with the association.

Here too, in this third Example of association with anacetylcholinesterase inhibitor, the increase in the power of contextualmemory observed cannot be explained by simply adding together theeffects of the compounds administered on their own.

In conclusion, the results presented above show synergistic activitybetween4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamide andgalantamine in terms of cognitive performance.

EXAMPLE D Irwin's Primary Observation Test

The effects, in terms of safety, of4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}-benzamide anddonepezil (both in the form of a hydrochloride), administered on theirown or in association, were studied using Irwin's primary observationtest in the C57B16 mouse (n=4 individuals per group).

Behavioural changes, physiological and neurotoxic symptoms, rectaltemperature and pupil diameter were recorded using a standardisedobservation grid derived from that of Irwin.

It was observed that4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamide (0.3and 1 mg/kg of base per os) and donepezil (0.1 and 0.3 mg/kg of base peros), administered on their own or in co-administration, brought about noobservable changes in Irwin's test in the mouse. At the strongest dose(1 mg/kg of base per os), donepezil administered on its own reducesreactivity to touch and causes slight sedation. No potentiation of theadverse effects of donepezil at 1 mg/kg is observed when it isco-administered with4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamide (0.3and 1 mg/kg of base per os). On the contrary, when4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamide at thestrongest dose (1 mg/kg of base per os) is co-administered withdonepezil at 1 mg/kg p.o., no sedation is observed, which suggests that4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamideantagonises the sedation caused by donepezil at 1 mg/kg p.o.

In conclusion, the results presented above demonstrate synergisticactivity between4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamide anddonepezil in terms of cognitive performance, this being the case with agood safety profile and without pharmacokinetic interaction.

1. A combination between4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamide offormula (I):

or an addition salt thereof with a pharmaceutically acceptable acid orbase, and an acetylcholinesterase inhibitor.
 2. The combinationaccording to claim 1, wherein the4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamide is inthe form of an oxalate or hydrochloride.
 3. The combination according toclaim 1, wherein the acetylcholinesterase inhibitor is selected fromdonepezil, rivastigmine, galantamine, and pharmaceutically acceptablesalts thereof.
 4. The combination according to claim 3, whereinacetylcholinesterase inhibitor is selected from donepezil hydrochloride,rivastigmine hydrogen tartrate, and galantamine hydrobromide.
 5. Thecombination according to claim 1, wherein4-{3-[cis-hexahydrocyclopenta[c]pyrrol-2(1H)-yl]propoxy}benzamide isadministered in the form of a hydrochloride at a daily dose of 2 mg, 5mg or 20 mg (expressed as base), and the acetylcholinesterase inhibitoris donepezil hydrochloride administered at a daily dose of 10 mg.